BOSTON, Ma. (WUSA9/AP) -- The second suspect, of the Boston Marathon bombings, Dzhokhar A. Tsarnaev, 19, has been caught, the mayor of Boston tweeted.

Boston Police also tweeted, "CAPTURED!!! The hunt is over. The search is done. The terror is over. And justice has won. Suspect in custody."

"We're exhausted, but we have a victory here tonight,'' said Col. Timothy Alben, State Police Superintendent.

The hunt to find Dzhokhar Tsarnaev had been ongoing since Thursday. The capture comes after a tense five days. He exchanged gunfire with law enforcement for an hour while holed up in a boat before being captured, said police.

"It was a very very complicated case. It was a very challenging case. There are still some questions remaining to be answered."

U.S. Attorney Carmen Ortiz said charges against Tsarnaev have not yet been determined. "This is still an active, on-going investigation,'' Ortiz said, adding that it will be Attorney General Eric Holder's decision whether to seek the death penalty.

The suspect is in serious condition according to the police commissioner.

Crowds near the site could be seen cheering around 8:45 p.m. on Friday.

Police responded en masse Friday evening after shots were fired in the town where a Boston Marathon bombing suspect was last seen. The suspect was located by a boat at 67 Franklin St. Watertown, Mass.

Shortly after the lockdown was lifted early Friday evening in the town where the at-large Marathon bombing suspect was last seen, journalists reported several shots could be heard. Later Friday evening, reporters said several explosions could be heard at the scene.

The brothers are suspects in Monday's marathon bombings, which killed three people and wounded more than 180 others. The men are also suspected of killing a Massachusetts Institute of Technology police officer in his vehicle late Thursday.

Secretary Napolitano said in a statement, "The apprehension of the suspect tonight is a significant development in the ongoing FBI-led investigation of the Boston bombings. I commend the federal, state and local law enforcement and first responders who have been and continue to work tirelessly to get to the bottom of the senseless attacks in Boston, and defend and protect the American public."

The mayor of Boston commended the work of all law enforcement agencies, at a press conference shortly after the suspect was apprehended alive, "I just want to say very briefly, thank you, thank you, thank you."